[ARM] clkdev: fix clock matching
The old matching algorithm was too fuzzy, causing false positives.
For example, when asked for device D connection C1 and we only find
device D connection C2, we return that as a valid match despite the
connection names being different.
Change the algorithm such that:
An entry with a NULL ID is assumed to be a wildcard.
If an entry has a device ID, it must match
If an entry has a connection ID, it must match
However, we maintain the order of precidence while still only doing
a single pass over all entries: dev+con > dev only > con only.
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
diff --git a/arch/arm/common/clkdev.c b/arch/arm/common/clkdev.c
index 17a17b4..1037bba 100644
--- a/arch/arm/common/clkdev.c
+++ b/arch/arm/common/clkdev.c
@@ -24,6 +24,15 @@
static LIST_HEAD(clocks);
static DEFINE_MUTEX(clocks_mutex);
+/*
+ * Find the correct struct clk for the device and connection ID.
+ * We do slightly fuzzy matching here:
+ * An entry with a NULL ID is assumed to be a wildcard.
+ * If an entry has a device ID, it must match
+ * If an entry has a connection ID, it must match
+ * Then we take the most specific entry - with the following
+ * order of precidence: dev+con > dev only > con only.
+ */
static struct clk *clk_find(const char *dev_id, const char *con_id)
{
struct clk_lookup *p;
@@ -31,13 +40,17 @@
int match, best = 0;
list_for_each_entry(p, &clocks, node) {
- if ((p->dev_id && !dev_id) || (p->con_id && !con_id))
- continue;
match = 0;
- if (p->dev_id)
- match += 2 * (strcmp(p->dev_id, dev_id) == 0);
- if (p->con_id)
- match += 1 * (strcmp(p->con_id, con_id) == 0);
+ if (p->dev_id) {
+ if (!dev_id || strcmp(p->dev_id, dev_id))
+ continue;
+ match += 2;
+ }
+ if (p->con_id) {
+ if (!con_id || strcmp(p->con_id, con_id))
+ continue;
+ match += 1;
+ }
if (match == 0)
continue;